Closure caps in the form of crown caps and container caps having a liner and a cap shell peelably bonded together have been used in the sale of bottled products where a prize marking indicating a prize has been included with the closure cap.
Crown caps or other container caps commonly used to date have comprised a sheet of metal which has been coated with a protective paint. The sheet is then formed into the shape of a crown shell or cap shell and a liner adhered to the inside of the formed shell. Where the caps are used with bottled beverages with which a prize is offered, the common practice has been to award a prize in exchange for a predetermined number of liners or a winning liner which is brought to a store by a consumer or a buyer. It is necessary that the crown cap or container have a liner which is easily peelable from the cap shell. At the same time, it is necessary that the liner adhere to the cap shell to such a degree that it will not come off during the process of forming the cap, during shipment of the cap or during bottle capping procedures. Furthermore, the shell must have a sufficient corrosion resistance against any contents of a bottle which might cause corrosion and this corrosion resistance must withstand climbing, roll-on and other forming processes. Moreover, from the standpoint of hygienics, any ink layer comprising any printed prize mark on the liner surface must not directly contact the bottled beverage and, considering that the liner itself is applied to the cap shell in the form of fluid, it is desirable that any ink layer applied on the inside of the cap shell be transferred and adhered to the liner when the liner is peeled off its shell.
In order to achieve the requirements outlined above, it has been proposed to utilize a crown cap having the cap shell and the liner bonded together through a peelable coating to coating interface. In such a crown shell the liner is bonded to the shell with a sufficient adhesion to prevent it from coming off the shell by vibration during transportation and corking of the cap. To peel such a coating to coating interface, it is necessary to break one of the coatings with a considerably large force. As a result, it is often difficult to peel the liner from the shell in such a manner that one of the coatings adheres completely to the liner to assure that an ink layer indicating a prize mark is transferred to the side of the liner in unbroken form.
Accordingly, it is an object of our invention to provide a closure cap comprising a cap shell and a liner bonded together through a peelable coating to coating interface, and including a peelable starting portion of the liner at which one of the coatings is easily broken. This will then permit the ink layer of a prize mark to transfer to the liner side in unbroken form together with the coating covering the ink layer.
Another object of the invention is to provide a closure cap with a liner having a provision for preventing accidental peeling of the liner from the shell but facilitating such peeling, if necessary, with fingers without the need of any special tools.